Method for seizing, and holding for transfer of small objects, particularly coiled filaments for electrical lamps and the like

ABSTRACT

A belt, preferably of polyethylene, for example about 50 Mu thick is provided which has cuts placed therein shaped to provide counter-directed projecting portions located essentially adjacent each other; in a preferred form, a single Z-shaped cut can be used. The belt is wrapped about a mandrel of small diameter, preferably less than the distance of the base portions of the cuts, so that when the belt is wrapped thereabout, the portions of the belt which project, between the cuts, will stand up to form flaps. The objects are dropped between the upstanding projections and when the belt is again straightened, the upstanding projections will resiliently hold the objects against the remainder of the belt, for transport and further processing, for example by immersing the belt with the objects in a chemical dissolving bath.

United States Patent [191 Dohllen et a1.

[ METHOD FOR SEIZING, AND HOLDING FOR TRANSFER OF SMALL OBJECTS, PARTICULARLY COILED FILAMENTS FOR ELECTRICAL LAMPS AND THE LIKE [75] Inventors: Klaus V. Dohlen, Landershofen;

Josef Lukas, Augsburg, both of Germany [73] Assignee: Patent-Freuhand-Gesellschaft fur elektrische Gluhlampen mbH,

Munchen, Germany 22 Filed: Jan .17, 1972 21 Appl.No.: 218,112

[30] Foreign Application Priority Data Germany 2105517 Feb. 5, 1971 [52 {1.5. CI 29/559, 29/25.1, 29/2517, 29/25.l9, 29/423, 198/131, 198/179, 269/321 WE 51] 1m. (:1 B23q 1/00 [58] Field of Search ..29/559, 25.1, 25.17, 423, 29/2511, 25.19; 140/715; 53/183; 269/321 CF, 321 WE; 198/179, 131; 206/59 [56] References Cited UNITED STATES PATENTS 2,280,573 4/1942 Flaws, Jr 53/28 X 2,372,072 3/1945 Flaws, Jr 53/28 X [451 Feb. 26, 1974 2,988,199 6/1961 Pinkham..- 198/179 X 3,110,098 11/1963 Sobierajski 29/423 3,120,892 2/1964 Henning et a1. 198/179 3,171,535 3/1965 Harris 198/131 FOREIGN PATENTS OR APPLICATIONS 471,746 9/1937 Great Britain 198/179 753,518 7/1956 Great Britain 198/179 Primary ExaminerCharles W. Lanham Assistant Examiner-Victor A. DiPalma Attorney, Agent, or FirmFlynn & Frishauf [5 7] ABSTRACT dropped between the upstanding projections and when the belt is again straightened, the upstanding projections will resiliently hold the objects against the remainder of the belt, for transport and further processing, for example by immersing the belt with the objects in a chemical dissolving bath.

9 Claims, 3 Drawing Figuresv s ay saw 1 'UF 3 FIG.1

PATENTEUFEBZB I874 SHEET 2 OF 3 .OOOOOOOOONVNVO NNNNNNNNNN A NNNNNNNNNNN PATENTEUFEBZSISM V 3,793,706

sum 3 OF 3 I The present invention relates to a method to seize, hold, and subsequently to transfer for treatment of small objects, and particularly coiled wire filaments for use in electrical incandescent lamps, electrodes of discharge lamps, and the like, which filaments are made after a production step which may include cutting off of filamentary items for individual lamps after having been made from a long continuous wire. The invention additionally relates to an apparatus capable of carrying out the method, and in which the filaments are individually seized, stored and packed in such a manner that they can be chemically treated.

The invention will be described in general with respect to filament coils for incandescent lamps, fluorescent lamps, and the like, and indeed was developed due to particular problems associated with the manufacture of such filaments, although it is applicable also to other small objects. When wire filaments for electrical lamps are made, the filaments are coiled about themselves and additionally coiled about a mandrel so that they can then be cut to size. The individual filaments, in cut length, around the mandrel are immersed in a suitable acid bath to dissolve the coil mandrel. Customarily this dissolution step has been carried out while the filaments are loose in a container. The acid dissolution bath for the mandrel is circulated in the chemical treatment vessel. Due to agitation and the circulating fluid,

the filaments become entangled. After drying, the entangled ball of filaments is fed to a separating device. The coils are then applied to an assembly or mounting machine. The considerable entanglement of the coils arising in the acid treatment bath interferes with separation, which disturbs normal production flow and permits damaged or not completely separated coils to be transported to the assembly station, which requires that they are separately sorted out. This is often done manually. Apart from the additional work entailed by the insufficient separation of the coils, the overall consumption of filament material is considerably increased due to the presence of damaged coils being supplied after separation, and the inability to separatesome coils at all.

Separated, single transport of filamentary coils in compartmented conveyoer belts has previously been proposed see U.S. Pat. No. 2,372,072 and-2,280,573 for reference. These patents describe conveyor belts which, after an optical control of filament coils, enclose the coils in compartments formed in the belt. Similarly, British Pat. Specification 75 3,5 l 8 describes a conveyor belt which, when it is guided over a sharply bent edge, is adapted to retain filament coils in slots formed in the belt which'open and close as the belt is guided over the bend. The techniques of both the US. Patents and the British Patent Specification enable transport of coils in single units; the difficulty of separating out the coils from a bunch, or ball of cut coils is not, however, removed. The belts are not suited to accept coils after having been cut, since the coils are retained in the belt in such a manner that they cannot, thereafter, be treated with a treatment fluid, such as an acid bath to etch out the mandrel. In accordance with the US. Patents, the coils are retained in small compartments which are dust-tight, so that the core or mandrel over which the coils are wound cannot thereafter be dissolved out. The type of belt disclosed which encloses the coils all over makes it difficult to optically or visually check and inspect the cut coils.

It is an object of the present invention to provide a method and an apparatus in which the disadvantages of the prior art are essentially removed and which permits single transport and handling of small objects, and in particular filamentarycoils for electrical lamps.

SUBJECT MATTER OF THE PRESENT INVENTION Briefly, a belt is provided, preferably of transparent polyethylene or the like, for example of 50 p. thickness, which has slots cut therein which leave, in the belt, at least two projecting portions which have directions of projection, one in the direction of transport of the belt and the other oppositely thereto. The projecting portions are connected with the belt at a base region remote from the projecting ends, which extend substantially transversely to the direction of transport. The belt is guided over an edge, typically a surface having a radius of curvature which is not more than half the distance between the connecting regions of the oppositely directed projections to the belt. As the belt is guided over this edge, the projections are deflected from their position which is essentially flat or plan with respect to the surface of the belt to an unstanding position where they will form upstanding flaps. At that point, the objects, typically the filament, are introduced singly into the space between the oppositely directed projections, for example by being dropped through a wheel having notches or separating grooves at the circumference thereof, into which the cut elements are dropped as they are being cut. The belt is then guided over an essentially straight surface so that the flaps will close over the objects, typically the filaments. The filaments are thus contacted only at selected surface portions thereof and the belt can be rolled over a substantially greater radius of curvature than the sharp edge and, with the filaments therein immersed in a dissolving bath so that the mandrels or cores for the filaments can be chemically dissolved out. The excellent chemicalresistance of polyethylene makes it a particularly suitable material for the belt, which can be reused. After the cores have been etched out, the belts can be directed to a filament feeding and insertion machine, thus facilitating the subsequent assembly of the filaments to the stems of a lamp press.

The filament coils thus are held in the belt in such a manner that they can be essentially completely con.- tacted by dissolving acid, the filamentary coils being separated so that they cannot hook into each other or become entangled. If optical, or visual inspection is desired, an optical test apparatus, such as binocular microscopes, ground glass projectors, photoelectric scanning apparatus or the like can readily be placed along the transport path, before and/or after the core has been etched out, the transparent belt permitting visual or optical inspection.

The invention will be described by way of example with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic side view of the apparatus, and illustrating the process; Y

FIG. 2 is a top view of a belt utilized in the process;

and FIG. 3 is an enlarged fragmentary side view illustrating the placement of filaments in the belt.

A continuous twist of filamentary material, wrapped around a mandrel and together schematically illustrated at 1 (FIG. 1) is cut into small length, for insertion in lamps, by a knife 3, the cutting operation itself being controlled by a cut control apparatus (which may be magnetic) schematically illustrated at 2. The knife and cutter control apparatus are well known in the art and need not be described in detail. The cut coils, with the core or mandrel portion inside is dropped on wheel 5 which rotates in the direction of the arrow. Wheel 5 has grooves or notches 6 formed on the circumference thereof. The cut filaments, schematically illustrated at 4, will thus be transported, one at a time, by wheel 5. Operations of the cutter 3'and the wheel 5 are synchronized, as well known. The wheel 5 rotates in a housing 7 which closely surrounds the wheel, to prevent the coils 4 from falling out. At the bottom, the housing is formed with a slit 8 which releases, singly, the cut coils 4.

A belt 9 (FIG. 2) is located beneath the slit 8. Belt 9, at its sides, has transport perforations 10 which are engaged by transport sprockets, as well known. The central portion of the belt has severing lines in the shape of a Z punched therein, as illustrated in three rows. The Z-shaped punches 11 provide two projecting portions, one portion 11a extending in the direction of transport, as indicated by-arrow A, and the other projecting portion, 11b, extending in the opposite direction. The portions included by the acute angle formed by the Z thus will form a pair of flaps 15, 16. The belt is made of a plastic foil material which is resistant to acids and bases; typically it is polyethylene, about 50 p. thick. The single, separated filaments are placed on the belt, and held thereby as best seen in the detail view of FIG. 3. Belt 9 is guided from a pay-out roll 12 (FIG. 1) over a guide roller 13 and then over a guide surface bar 14 (FIG. 3) which has, at its tip, a curvature of such diameter, or distance, that the counter-directed flaps l5, 16 will stand up, and become erect as the belt is guided over the edge of member 14 (see FIG. 3). Just as the opening between the flaps is in alignment with slit 8 (FIG. I), synchronized feed of the belt and the wheel 5 will present a notch 6, filled with a cut filament 4 which will drop, by gravity,'into the space between the flaps. If the filament is long enough to span the width of the belt, and is to be held, a plurality of rows can be formed on the belt, three being shown on FIG. 2. The belt can also be made wider, and a plurality of filaments aligned in rows on the belt, fed from drums formed with compartmented notches or grooves.

As the perforated belt is guided over an angle of 180, the flaps 15, 16, as they become erect, will form a pocket which is open at the bottom. Drive wheel 17 (FIG. 1) transports the belt along the longitudinal, essentially straight side surface of member 14 and the projecting ends 11a, 1119, which form the flaps 15, 16 willclose over the filament coils. The belt is then wound on a spool 18. The spool center or core is also made of a plastic material which is acid and base resistant, such as PVC. The spool on which the belt is to be wound is so dimensioned that .it may serve as carrier for the belt holding the filaments during the dissolution step during which the core is dissolved out. The completed spool, with belt, is introduced into an acid bath B (FIG. 1). The acid can be circulated, or agitated, as

well known. The liquid has access to the filaments held in the belt from all sides, yet entanglement of the individual filaments is prevented.

After the cores have been dissolved, the belt with the filaments thereon is washed in order to remove remnants of the dissolving acid bath, and then dried with warm or hot air. The spool, together with the belt and the now hollow filamentary coils is taken to the mounting apparatus for the lamp press, where the belt is unwound and the filaments are inserted in a conventional coil board or are directly inserted, for example by a vacuum gripper to the pinch apparatus for the leads, for pinch-sealing the filament. The coils can be taken, singly, directly from the belts. In order to remove the coils, the belt filled with the coils is guided once more over a surface which opens the flaps, that is, a surface similar to element 14 (FIG. 3). The now empty belt can be respooled on a supply reel 12 for re-use.

Optical or visual inspection can be carried out at any desired point I in the process. The belt on wind-up reel 18 can be separately re-spooled to another coil for inspection, which enhances the versatility of the apparatus and the method since inspection can be carried out, singly and on the separated coils, the belt on the spool permitting ready transport. Coupled with the inspection, a test step can be carried out and defective coils removed, on their position marked so they will not be inserted into clamps at a later insertion stage.

Various changes and modifications can be made within the inventive concept.

The cut for projecting portions need not be Z- shaped, but can be trapezoidal, V-shaped, without lateral interconnection; the Z-shaped cuts being a special and particularly simple form of a pair of connected V- shaped projections.

We claim:

1. Method of seizing, treating in a solvent bath, holding for transfer, and releasing small filamentary coils for lamp filaments comprising providing a transparent foil forming a transport belt essentially inert with respect to the solvent bath and having cuts which define at least two projecting portions, one having a direction of projection in the direction of transport of the belt and the other having a direction of projection opposite the transport direction, the projecting portions being connected with the belt at a region remote from said projections and extending substantially transverse to the direction of transport;

guiding said belt over a surface having a sharp radius of curvature to deflect the cut projecting portions from their position with respect to the surface of the belt as the belt is bent and to form outwardly projecting flaps;

introducing a single filamentary coil on the belt in the space between the oppositely directed projecting flaps as the belt is guided over said sharply bent surface and at a location opposite said surface;

subsequently moving said belt over a path having a maximum radius of curvature which is substantially less than that of the sharp bend, to permit said flaps to close over the coils;

subjecting the belt and the coils held thereon to a solvent bath; optically inspecting the filament coils as they are held between the projections of the transparent belt;

and guiding the belt over a surface which has a radius of curvatures similar to said sharp radius of curvature to release the coils being held between oppositely directing flaps and to retrieve the coils from the belt. 1

2. Method according to claim 1, wherein the step of guiding the belt over a surface having a sharp radius of curvature comprises guiding the belt over a surface having a radius of curvature which is up to about half of the distance of the connecting regions of a pair of oppositely directed projecting portions.

3. Method according to claim 1, wherein the cuts are interconnected.

4. Method according to claim 3, wherein the cuts form a continuous cut which is, in plan outline, approximately Z-shaped.

5. Method according to claim 1, wherein the belt is a polyethylene ribbon in the order of about 50 p. thick.

6. In the method of manufacturing filamentary coils I for lamp filaments, in which filaments material is wound on a dissolvable core, the step of:

feeding a length of core material, with filaments wound thereon;

cutting said core and filaments in length;

passing a receptacle beneath the cut length, in time synchronism with the cutting operation, one receptacle, each, being presented for each cut length;

providing a chemical solvent bath in which the core material for the filamentary material is dissolvable;

predetermined positions with respect to the surface of the belt as the belt is bent and to fonn outwardly projecting flaps, said surface having said sharp radius being in proximity to the receptacles carrying single cut cores and filaments wound thereon, the guiding movement of said belt being synchronized with the movement of said receptacles to present deflected cut projections each time a receptacle appears opposite said cut surface, to load one cut core and filament thereon between said projecting portions;

subsequently moving said belt over a path having a maximum radius of curvature which is substantially less than that of the sharp bend, to permit said flaps to close over the filaments wound on the core; subjecting the filaments wound on the cores, held on the belt, to a solvent bath of such composition that the cores are dissolved, said projecting portions retaining said unsupported coils in position on the belt, said step subjecting the belt to the solvent bath including'contacting the coils and dissolving cores with turbulence; removing the belt and the filaments, after dissolution of the cores from the filaments from said bath; optically inspecting the filament coils as they are held between the projections of the transparent belts; and guiding the belt over a surface which has a radius of curvature similar to said sharp radius of curvature to release the filaments being held between oppositely directing projecting portions and to retrieve the filaments from the belt for assembly of the filaments into lamps.

7. Method according to claim 6, wherein the step of guiding the belt over a surface having a sharp radius of curvature comprises guiding the belt over a surface having a radius of curvature which is up to about half of the distance of the connecting regions of a pair of oppositely directed projecting portions.

8. Method according to claim 6, wherein the cuts form a continuous cut which is, in plan outline, approximately Z-shaped.

9. Method according to claim 6, wherein the belt is a polyethylene ribbon in the order of about 5011. thick. i

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. IL 79L706 Dated Febraur ,26 1974 Inventor(s) Klaus V. DOHLEN and Josef LUKAS It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Patent=Ireuhand-Gesellschaft f'dr Assignee:

elektrische Gluhlampen mbH Inventor: Klaus y DOHLEN Signed and sealed this 30th day of July 19%..

(SEAL) Attest:

MCCOY M. GIBSON, JR. 0. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 603764 69 w u.s. GOVERNMENT rnnn'ms ornc: In! o-su-su. 

1. Method of seizing, treating in a solvent bath, holding for transfer, and releasing small filamentary coils for lamp filaments comprising providing a transparent foil forming a transport belt essentially inert with respect to the solvent bath and having cuts which define at least two projecting portions, one having a direction of projection in the direction of transport of the belt and the other having a direction of projection opposite the transport direction, the projecting portions being connected with the belt at a region remote from said projections and extending substantially transverse to the direction of transport; guiding said belt over a surface having a sharp radius of curvature to deflect the cut projecting portions from their position with respect to the surface of the belt as the belt is bent and to form outwardly projecting flaps; introducing a single filamentary coil on the belt in the space between the oppositely directed projecting flaps as the belt is guided over said sharply bent surface and at a location opposite said surface; subsequently moving said belt over a path having a maximum radius of curvature which is substantially less than that of the sharp bend, to permit said flaps to close over the coils; subjecting the belt and the coils held thereon to a solvent bath; optically inspecting the filament coils as they are held between the projections of the transparent belt; and guiding the belt over a surface which has a radius of curvatures similar to said sharp radius of curvature to release the coils being held between oppositely directing flaps and to retrieve the coils from the belt.
 2. Method according to claim 1, wherein the step of guiding the belt over a surface having a sharp radius of curvature comprises guiding the belt over a surface having a radius of curvature which is up to about half of the disTance of the connecting regions of a pair of oppositely directed projecting portions.
 3. Method according to claim 1, wherein the cuts are interconnected.
 4. Method according to claim 3, wherein the cuts form a continuous cut which is, in plan outline, approximately Z-shaped.
 5. Method according to claim 1, wherein the belt is a polyethylene ribbon in the order of about 50 Mu thick.
 6. In the method of manufacturing filamentary coils for lamp filaments, in which filaments material is wound on a dissolvable core, the step of: feeding a length of core material, with filaments wound thereon; cutting said core and filaments in predetermined length; passing a receptacle beneath the cut length, in time synchronism with the cutting operation, one receptacle, each, being presented for each cut length; providing a chemical solvent bath in which the core material for the filamentary material is dissolvable; providing a transparent foil forming a transport belt essentially inert with respect to the solvent bath and having cuts which define at least two projecting portions, one having a direction of projection in the direction of transport of the belt and the other having a direction of projection opposite the transport direction, the projecting portions being connected with a belt at a region remote from said projections and extending substantially transversely to the direction of transport; guiding said belt over a surface having a sharp radius of curvature to deflect the cut projection from their positions with respect to the surface of the belt as the belt is bent and to form outwardly projecting flaps, said surface having said sharp radius being in proximity to the receptacles carrying single cut cores and filaments wound thereon, the guiding movement of said belt being synchronized with the movement of said receptacles to present deflected cut projections each time a receptacle appears opposite said cut surface, to load one cut core and filament thereon between said projecting portions; subsequently moving said belt over a path having a maximum radius of curvature which is substantially less than that of the sharp bend, to permit said flaps to close over the filaments wound on the core; subjecting the filaments wound on the cores, held on the belt, to a solvent bath of such composition that the cores are dissolved, said projecting portions retaining said unsupported coils in position on the belt, said step subjecting the belt to the solvent bath including contacting the coils and dissolving cores with turbulence; removing the belt and the filaments, after dissolution of the cores from the filaments from said bath; optically inspecting the filament coils as they are held between the projections of the transparent belts; and guiding the belt over a surface which has a radius of curvature similar to said sharp radius of curvature to release the filaments being held between oppositely directing projecting portions and to retrieve the filaments from the belt for assembly of the filaments into lamps.
 7. Method according to claim 6, wherein the step of guiding the belt over a surface having a sharp radius of curvature comprises guiding the belt over a surface having a radius of curvature which is up to about half of the distance of the connecting regions of a pair of oppositely directed projecting portions.
 8. Method according to claim 6, wherein the cuts form a continuous cut which is, in plan outline, approximately Z-shaped.
 9. Method according to claim 6, wherein the belt is a polyethylene ribbon in the order of about 50 Mu thick. 